This is a very surface level analysis like saying that the automobile was just an iterative improvement over a horse. Or a computer is just a better abacus. Fundamental research is all about diving into the weeds and finding new problems to solve. It's true that some of the "low hanging fruit" no longer exists (you won't see someone like Euler or Newton who's names pop up all over the place), but I can promise you that real gains are being made on a lower level. These small gains in fundamental research snowball into bigger advancements. As an example, the transformer architecture used by LLMs was first published in 2017.
Automobile was improvement over the horse because things needed to get places. To improve on current automobile will require either massive government investment and regulation in the sense of flying cars, or full electrification with paradigm shifts in transportation, like induction charging roads or battery hot swaps or whatever else. The modern Corolla Hybrid is pretry much the peak optimal point of transportation.
What do humans need right now to improve their lives substantially?
high temperature superconducting would cause a big leap. cheap energy would also help. cheap compute-in-the-walls. machines doing all the dangerous jobs.
Cheap energy is possible now with solar. There is a reason why it hasn't been done yet. Nobody has a need for it. Remember, you may think it would be nice to have an electric car you can charge for microcents a mile, but most people dgaf about putting gas in their car.
Machines doing dangerous jobs also is a thing these days.
High temperature superconducting can potentially be useful in a few applications that involve high current, which mostly deal with transportation. The only real advantage of this is drone delivery service becoming cheaper, but that has big hurdles to cross.
There is a reason why being a streamer is the top choice of "what I wanna be" when you ask kids. Everything is about the internet now in terms of motivation. And unfortunately there, we already hit a hard limit of the speed of light.
